Answer:
10 adult tickets cost £75 , 20 child tickets cost £60
Explanation:
let a be the cost of an adult ticket and c the cost of a child ticket , then
4a + c = 33 → (1)
2a + 7c = 36 → (2)
multiplying (2) by - 2 and adding to (1) will eliminate a
- 4a - 14c = - 72 → (3)
add (1) and (3) term by term to eliminate a
0 - 13c = - 39
- 13c = - 39 ( divide both sides by - 13 )
c = 3
substitute c = 3 into either of the 2 equations and solve for a
substituting into (1)
4a + 3 = 33 ( subtract 3 from both sides )
4a = 30 ( divide both sides by 4 )
a = 7.5
the cost of an adult ticket is £7.50
then 10 adult tickets cost 10 × £7.50 = £75
the cost of a child ticket is £3
the cost of 20 child tickets is 20 × £3 = £60